Earth-working apparatus having power-driven rotors that carry a plurality of generally L-shaped tines arranged radially about the shaft and in a spiral pattern along the shaft have heretofore been provided for agricultural tilling, road building and the like. Examples of prior U.S. patents illustrative of this type of apparatus are Lilleberg U.S. Pat. No. 1,415,663, Riddle U.S. Pat. No. 3,362,482, and Takata U.S. Pat. No. 3,702,638.
Recent developments in this art, particularly for agricultural tilling, have been toward wider and heavier apparatus that will cut a wider swath of material, as exemplified in Takata U.S. Pat. No. 3,746,101 and van der Lely U.S. Pat. No. 4,151,883. Wider and heavier tilling apparatus requires durable, robust construction that will withstand the pounding, twisting and shock stresses on a heavier rotor, including instances where hard objects are struck. In addition, wider apparatus requires more power to turn the heavier rotor.
Additional tilling width may be provided by using fold-up sections. An example of prior art related to fold-up wings on non-driven blades is shown in Poland U.S. Pat. No. 4,050,523. The disclosure of this patent, however, is of a non-driven tool and does not deal with the problem of the heavier power-driven tine assemblies such as those of the present invention.